arch/x86/kernel/cpu/scattered.c

   1 /*
   2  *      Routines to identify additional cpu features that are scattered in
   3  *      cpuid space.
   4  */
   5 #include <linux/cpu.h>
   6
   7 #include <asm/pat.h>
   8 #include <asm/apic.h>
   9 #include <asm/processor.h>
  10
  11 #include "cpu.h"
  12
  13 struct cpuid_bit {
  14         u16 feature;
  15         u8 reg;
  16         u8 bit;
  17         u32 level;
  18         u32 sub_leaf;
  19 };
  20
  21 /*
  22  * Please keep the leaf sorted by cpuid_bit.level for faster search.
  23  * X86_FEATURE_MBA is supported by both Intel and AMD. But the CPUID
  24  * levels are different and there is a separate entry for each.
  25  */
  26 static const struct cpuid_bit cpuid_bits[] = {
  27         { X86_FEATURE_APERFMPERF,       CPUID_ECX,  0, 0x00000006, 0 },
  28         { X86_FEATURE_EPB,              CPUID_ECX,  3, 0x00000006, 0 },
  29         { X86_FEATURE_CAT_L3,           CPUID_EBX,  1, 0x00000010, 0 },
  30         { X86_FEATURE_CAT_L2,           CPUID_EBX,  2, 0x00000010, 0 },
  31         { X86_FEATURE_CDP_L3,           CPUID_ECX,  2, 0x00000010, 1 },
  32         { X86_FEATURE_CDP_L2,           CPUID_ECX,  2, 0x00000010, 2 },
  33         { X86_FEATURE_MBA,              CPUID_EBX,  3, 0x00000010, 0 },
  34         { X86_FEATURE_HW_PSTATE,        CPUID_EDX,  7, 0x80000007, 0 },
  35         { X86_FEATURE_CPB,              CPUID_EDX,  9, 0x80000007, 0 },
  36         { X86_FEATURE_PROC_FEEDBACK,    CPUID_EDX, 11, 0x80000007, 0 },
  37         { X86_FEATURE_MBA,              CPUID_EBX,  6, 0x80000008, 0 },
  38         { X86_FEATURE_SME,              CPUID_EAX,  0, 0x8000001f, 0 },
  39         { X86_FEATURE_SEV,              CPUID_EAX,  1, 0x8000001f, 0 },
  40         { 0, 0, 0, 0, 0 }
  41 };
  42
  43 void init_scattered_cpuid_features(struct cpuinfo_x86 *c)
  44 {
  45         u32 max_level;
  46         u32 regs[4];
  47         const struct cpuid_bit *cb;
  48
  49         for (cb = cpuid_bits; cb->feature; cb++) {
  50
  51                 /* Verify that the level is valid */
  52                 max_level = cpuid_eax(cb->level & 0xffff0000);
  53                 if (max_level < cb->level ||
  54                     max_level > (cb->level | 0xffff))
  55                         continue;
  56
  57                 cpuid_count(cb->level, cb->sub_leaf, &regs[CPUID_EAX],
  58                             &regs[CPUID_EBX], &regs[CPUID_ECX],
  59                             &regs[CPUID_EDX]);
  60
  61                 if (regs[cb->reg] & (1 << cb->bit))
  62                         set_cpu_cap(c, cb->feature);
  63         }
  64 }